Crack Paths 2012

where, KI, KII and KIII are the stress intensity factors for the three fracture modes,

respectively, which are obtained from the simulation. KIC, KIIC and KIIIC denote the

individual fracture toughness values of the three fracture modes. The constant

parameters , and should be empirically determined, we taken it as Eq. 4 [10].

1 ) ( ) ( II I 2 K K

(4)

IC K K

IIC 2

S T A T E M EONFTP R O B L EA MN DS I M U L A T IPO NR O C E D U R E

Simulation Model of the Problem

In building, the window glass is embedded into window frames for fixing, and about

2cm is shaded by the frame. In case of fire, the shaded area are not expose to the fire

radiation directly, therefore, the temperature is lower than the central part of the glass.

The central part of the glass temperature rising is mainly dominated by the radiation

from the fires. The shaded area temperature rise is caused by the heat conduction from

the central parts of the glass itself and the heated frame. In general, the shaded area

temperature rise is smaller than that of the central parts of the glass. At the back side of

the glass, the temperature rise is controlled by the heat conduction rate from the front

side and heat convection rate to the environment. This temperature is smaller than that

of the front part of the glass too. The temperature differences between the shaded part

and the uncovered part, between back side and the front side will build up the thermal

stress between them because of its expansion.

4

E2

2

3

B2

E1

B1

1

(b)

(a)

Fig. 1 Glass heated conditions. (a) E1 is exposing fire and E2 is shaded by frame; (b) B1

is the back side of fire and B2 is shaded by frame.

101